And if your cellphone didn’t make a loud noise coupled with a text-like message about two missing children, the phone model might be too old or your carrier doesn’t participate in the voluntary program that began Jan. 1.

But most carriers, including AT&T, Verizon, T-Mobile and Sprint, are part of the system to send out the alerts, said Brian Josef, assistant vice president of regulatory affairs for CTIA-The Wireless Association. He said 98 percent of U.S. carriers are in it.

LtoR Heather Rosas-Davis Brittney Rosas and Alan McNabb all friends of Hannahs listen as friends and family talk about Hannah to a large crowd of well wishers during a vigil at El Capitan High School Tuesday.
— Sean M. Haffey

Yes
32% (100)

No
68% (217)

317 total votes.

The search for two missing children out of Boulevard in East County triggered Monday night’s alert, and some carriers sent out multiple text messages about it. The case marked the first time that state officials hit the switch on the cellphone notification, said Erin Komatsubara, a spokeswoman with the California Highway Patrol, which runs the Amber Alert program.

Sheriff’s investigators asked for the alerts to help find James DiMaggio, 40, and two children he is suspected of abducting, Hannah Anderson, 16, and her brother, Ethan, 8.

The children’s mother was found dead Sunday in DiMaggio’s burned-out home. The remains of a child and a dog also were found.

“We are certainly hoping that this technology helps in finding this man and these children,” sheriff’s spokeswoman Jan Caldwell said.

Because the suspect and missing children could be anywhere, the alert was statewide and that’s what triggered the cellphone notification, Komatsubara said.

Steve Vaus, a Poway City Council member and iPhone 5 user, said he grabbed his phone when it shrilled but quickly grew frustrated. He moved to open the phone to read the message, but the alert text disappeared.

“I thought it was somewhere deep in the phone, but it was gone. Completely,” Vaus said. He called the statewide alert “a great idea but not well executed.”

Andrew Anguiano, 20, of Oceanside thought something was wrong with his phone when he got his first alert about 6 p.m. “Out of nowhere, it says Amber Alert,” he said.

When he got a second alert around 11 p.m., he became more curious and went online to find out about the case. “It’s a good idea that we have these,” he said.

But Jose Hernandez, 48, of Oceanside said the two alerts he got woke him up and he had no idea why he was getting them. “I just turned off my phone,” he said.

The text-like messages are targeted at phones in a specific geographic area, according to the Federal Communications Commission.

Alerts are sent from cell towers to reach nearby users of mobile devices so the messages get to the people most affected. So a New York tourist visiting Balboa Park on Monday could have gotten the same alert message as a San Diego resident sitting at home.